Tutorial by Examples: i

Import the ElementTree object, open the relevant .xml file and get the root tag: import xml.etree.ElementTree as ET tree = ET.parse("yourXMLfile.xml") root = tree.getroot() There are a few ways to search through the tree. First is by iteration: for child in root: print(child.ta...

(Note: All examples using let are also valid for const) var is available in all versions of JavaScript, while let and const are part of ECMAScript 6 and only available in some newer browsers. var is scoped to the containing function or the global space, depending when it is declared: var x = 4; /...

What is hoisting? Hoisting is a mechanism which moves all variable and function declarations to the top of their scope. However, variable assignments still happen where they originally were. For example, consider the following code: console.log(foo); // → undefined var foo = 42; console.log(fo...

Importing using base R Comma separated value files (CSVs) can be imported using read.csv, which wraps read.table, but uses sep = "," to set the delimiter to a comma. # get the file path of a CSV included in R's utils package csv_path <- system.file("misc", "exDIF.csv&q...

By default, a Date object is created as local time. This is not always desirable, for example when communicating a date between a server and a client that do not reside in the same timezone. In this scenario, one doesn't want to worry about timezones at all until the date needs to be displayed in lo...

A very simple way to import data from many common file formats is with rio. This package provides a function import() that wraps many commonly used data import functions, thereby providing a standard interface. It works simply by passing a file name or URL to import(): import("example.csv&quot...

Java SE 7 As the try-catch-final statement example illustrates, resource cleanup using a finally clause requires a significant amount of "boiler-plate" code to implement the edge-cases correctly. Java 7 provides a much simpler way to deal with this problem in the form of the try-with-res...

Employ the EAFP coding style and try to open it. import errno try: with open(path) as f: # File exists except IOError as e: # Raise the exception if it is not ENOENT (No such file or directory) if e.errno != errno.ENOENT: raise # No such file or directory ...

Final classes When used in a class declaration, the final modifier prevents other classes from being declared that extend the class. A final class is a "leaf" class in the inheritance class hierarchy. // This declares a final class final class MyFinalClass { /* some code */ } ...

Convert to String var date1 = new Date(); date1.toString(); Returns: "Fri Apr 15 2016 07:48:48 GMT-0400 (Eastern Daylight Time)" Convert to Time String var date1 = new Date(); date1.toTimeString(); Returns: "07:48:48 GMT-0400 (Eastern Daylight Time)" Conve...

The and-operator (&&) and the or-operator (||) employ short-circuiting to prevent unnecessary work if the outcome of the operation does not change with the extra work. In x && y, y will not be evaluated if x evaluates to false, because the whole expression is guaranteed to be false....

Introduction Package is a term used by npm to denote tools that developers can use for their projects. This includes everything from libraries and frameworks such as jQuery and AngularJS to task runners such as Gulp.js. The packages will come in a folder typically called node_modules, which will a...

# Set the repository for the scope "myscope" npm config set @myscope:registry http://registry.corporation.com # Login at a repository and associate it with the scope "myscope" npm adduser --registry=http://registry.corporation.com --scope=@myscope # Install a package &quo...

You will first need to create a directory, access it in your shell and install Express using npm by running npm install express --save Create a file and name it app.js and add the following code which creates a new Express server and adds one endpoint to it (/ping) with the app.get method: const e...

A dictionary is an example of a key value store also known as Mapping in Python. It allows you to store and retrieve elements by referencing a key. As dictionaries are referenced by key, they have very fast lookups. As they are primarily used for referencing items by key, they are not sorted. crea...

Python 3.2+ has support for %z format when parsing a string into a datetime object. UTC offset in the form +HHMM or -HHMM (empty string if the object is naive). Python 3.x3.2 import datetime dt = datetime.datetime.strptime("2016-04-15T08:27:18-0500", "%Y-%m-%dT%H:%M:%S%z"...

Dates don't exist in isolation. It is common that you will need to find the amount of time between dates or determine what the date will be tomorrow. This can be accomplished using timedelta objects import datetime today = datetime.date.today() print('Today:', today) yesterday = today - date...

The $_SESSION variable is an array, and you can retrieve or manipulate it like a normal array. <?php // Starting the session session_start(); // Storing the value in session $_SESSION['id'] = 342; // conditional usage of session values that may have been set in a previous session if(!i...

Parameters can be used for returning one or more values; those parameters are required to be non-const pointers or references. References: void calculate(int a, int b, int& c, int& d, int& e, int& f) { c = a + b; d = a - b; e = a * b; f = a / b; } Pointers: ...

C++11 The type std::tuple can bundle any number of values, potentially including values of different types, into a single return object: std::tuple<int, int, int, int> foo(int a, int b) { // or auto (C++14) return std::make_tuple(a + b, a - b, a * b, a / b); } In C++17, a braced init...